Comparisons between primary care morbidity-recording systems are often impossible due to divergent terms and definitions of rates. Attaining uniformity in family practice research is thus a major element of this project. A Glossary of Family Practice Terminology is being prepared. Alternative methods of estimating the populations served by individual family practices are being refined. The ultimate goal: to predict the required number and optimal distribution of family practitioners throughout Virginia from 1980 to 2000. The Virginia Family Practice Data System, a continuous record system designed to reflect all problems seen by participating family practitioners, is our data source. Five teaching and sixteen community practices serving a range of patient populations are currently recording morbidity using the International Classification of Health Problems in Primary Care. Analytical techniques to estimate the number of "non-visiting patients" tested on data from the English Second National Morbidity Survey (1970-71) are being applied to Virginia records. Distributions of visits, episodes, and problems recorded are being fitted to the negative binomial to derive estimates of non-visiting patients. Sample surveys based on patient demographic information files and "activity" analyses using patient charts are additional approaches to verify the distributional method.